1. Field of the Invention
The present invention relates to a safety apparatus and, more particularly, to such a safety apparatus which interoperates with conventional machines, such as cotton lint cleaners and the like, to proscribe a secure zone about the operative components thereof so as to protect personnel from injury.
2. Description of the Prior Art
Industry is dependent upon the use of mechanical devices, and particularly heavy machinery, in performing the required processes. Typically a multiplicity of manufacturing steps must be performed in sequence at a rapid pace in order to ensure that a sufficient volume is produced consistent with the price range required of the marketplace. In order to maintain such volume while minimizing overhead expense, the industrial age has seen heavy reliance on machinery to perform the required steps. While the use of such machinery has produced increasingly dramatic increases in productivity, the hazards associated with such productivity are ever present.
For example, in the commercial production of cotton fiber, various machines are required to process the fiber prior to it being compressed into bales for sale to other industries which use the cotton fiber for the manufacture of other products. One of the machines employed in such ginning operations, and usually in banks or batteries of such machines, is the lint cotton cleaning machine. Such machines operate to remove leaf particles, motes, grass and bark left in the cotton fiber after processing by seed cotton cleaners and extractors. In most ginning operations, batteries of such lint cleaning machines are employed at two or more stages in the ginning operation.
Lint cleaning machines are characterized by the use of a condenser screen drum to form the cotton fiber into a batt which is removed from the condenser screen drum by two doffing rollers and fed through one or more sets of compression rollers. Thereafter, the batt is passed between a very closely fitted feed roller and feed plate or bar and fed onto a saw cylinder. Each set of compression rollers rotates slightly faster than the preceding series of rollers which causes the batt to be thinned to some degree. The feed roller and plate grip the batt so that a combing action takes place as the saw teeth seize the cotton fiber. The tolerances involved in the spacing of the elements of the lint cleaning machine are very small. For example, the feed plate clears the saw cylinder by only about one-sixteenth of an inch. A doffing brush assembly removes lint from the saw cylinder and passes it from the lint cleaning machine for further processing.
Since such lint cleaning machines operate at a very high velocity in substantially continuous operation during the season, their operation must be monitored so as immediately to be able to detect breakdown and to remove blockage that may develop very rapidly. Still another condition which must be monitored is that of fire caused by the cotton fiber being heated during passage through the lint cleaning machine.
The rapid development of clogging or burning cotton fiber in the area of the compression rollers is the triggering event for injury to personnel. Such accidents occur when personnel attempt to gain access to the interior of the lint cleaning machine for the removal of excess or burning cotton fiber before the saw cylinder and/or feed rollers have come to a complete stop. As a direct consequence of the high inertial load of the saw cylinder, the time required for the saw cylinder to come to a complete stop is approximately two minutes in conventional machines. The aggravation of the condition during that two minute period as witnessed by such personnel constitutes an overbearing motivation for personnel to attempt to alleviate the problem even before such movement of the saw cylinder and feed rollers is terminated.
Whereas, lint cleaning machines are not the most frequent cause of accidents in the ginning industry, the accidents resulting therefrom account for the most debilitating and costly injuries. These injuries most commonly occur from removal of the access grates of the machines by personnel prior to the machine coming to rest and the insertion of fingers between the compression rollers. Since the compression rollers draw the fingers into the machine, the most gruesome injuries can take place. In order to prevent such injuries, various prior art methods have been employed to prevent removal of the access grates. However, once the operative parts of the lint cleaning machine come to a stop, the access grates must rapidly be removed to correct the particular problem. Prior art methods have not permitted sufficiently rapid removal of the access grates and therefore are frequently not used even though available. They have thus not proved satisfactory.
Therefore, it has long been known that it would be desirable to have a safety apparatus which can be employed on machinery to prevent access to the interior thereof during an operative mode, but which permits immediate access to the interior once the machine has reached an inoperative mode; which has particular utility in use on such heavy equipment as lint cleaning machines employed in cotton ginning operations; and which operates inexpensively and completely dependably to preclude injury to personnel as a result of gaining access to the interior of such machinery prior to reaching the inoperative mode.